Avian Backplate Motor Mount, 35-42mm is compatible with the Spektrum Avian 3530-1250kv Outrunner Brushless Motor (SPMXAM4595), Spektrum Avian 3536-1200kv Outrunner Brushless Motor (SPMXAM4620), Spektrum Avian 4240-1000kv Outrunner Brushless Motor (SPMXAM4675), Spektrum Avian 4250-800kv Outrunner Brushless Motor (SPMXAM4700) and Spektrum 4260-800kv Outrunner Brushless Motor (SPMXAM4725).